What made humans modern? The urge to adorn, scholars say
Page 2 of 2 -- The beads, the shells of a species of tiny mollusk-scavenging creatures that live in estuaries, were apparently brought to Blombos Cave from rivers about 12 miles away, suggesting that the prehistoric people were exploring their environment, and probably met up with members of other hunter-gatherer groups.
Henshilwood and his colleagues said the shells seem to have been selected by size, and holes apparently were drilled into them -- perhaps using pointed stone tools. They may have been strung on plant-fiber twine or on dried animal sinews, and they still carry traces of red ochre pigment that may have been painted on the beads, or rubbed off the wearer, covered in body paint.
Dating was done by detailed analysis of thousands of grains of sand in the cave, a technique that suggested the beads were about 75,000 years old. There is still some dispute among geologists, however, about the accuracy of this "optically-stimulated luminescence" dating technique. Henshilwood has not submitted the beads for radiocarbon dating.
Anthropologist Richard G. Klein, who has also worked extensively at excavations in South Africa, said he thinks the shells could be 75,000 years old, but he's not yet convinced they were beads. The holes might have been an accident of nature, rather than man-made.
"It seems strange that the perforations [in the shells] show no wear or marks from pressing against cord or string," said Klein, a professor at Stanford University, adding that he wishes Henshilwood had addressed that point in his article.
Klein said he's also concerned that the finds at Blombos Cave are similar to finds in only two or three African sites, while there are at least 40 other sites of the same age that don't show similar intellectual development.
The reason bead-making and other symbol-making became commonplace "is probably because the behaviors they reflect greatly enhanced survival and reproduction, and this makes it hard to understand why they would remain rare for so long before 40,000 years ago," Klein said, adding that art became a universal human experience at that point. "My view is that the occurrences before 40,000 years ago are the kind of noise that is inevitable in the archeological record."